/* -*-	Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/*
 * Copyright (C) Xerox Corporation 1997. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linking this file statically or dynamically with other modules is making
 * a combined work based on this file.  Thus, the terms and conditions of
 * the GNU General Public License cover the whole combination.
 *
 * In addition, as a special exception, the copyright holders of this file
 * give you permission to combine this file with free software programs or
 * libraries that are released under the GNU LGPL and with code included in
 * the standard release of ns-2 under the Apache 2.0 license or under
 * otherwise-compatible licenses with advertising requirements (or modified
 * versions of such code, with unchanged license).  You may copy and
 * distribute such a system following the terms of the GNU GPL for this
 * file and the licenses of the other code concerned, provided that you
 * include the source code of that other code when and as the GNU GPL
 * requires distribution of source code.
 *
 * Note that people who make modified versions of this file are not
 * obligated to grant this special exception for their modified versions;
 * it is their choice whether to do so.  The GNU General Public License
 * gives permission to release a modified version without this exception;
 * this exception also makes it possible to release a modified version
 * which carries forward this exception.
 */

#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /cvsroot/nsnam/ns-2/apps/udp.cc,v 1.21 2005/08/26 05:05:28 tomh Exp $ (Xerox)";
#endif

#include "udp.h"
#include "rtp.h"
#include "random.h"
#include "address.h"
#include "ip.h"

#include <stat.h>

static class UdpAgentClass : public TclClass {
public:
	UdpAgentClass() : TclClass("Agent/UDP") {}
	TclObject* create(int, const char*const*) {
		return (new UdpAgent());
	}
} class_udp_agent;

UdpAgent::UdpAgent() : Agent(PT_UDP), seqno_(-1)
{
	bind("packetSize_", &size_);
}

UdpAgent::UdpAgent(packet_t type) : Agent(type)
{
	bind("packetSize_", &size_);
}

// put in timestamp and sequence number, even though UDP doesn't usually
// have one.
void UdpAgent::sendmsg(int nbytes, AppData* data, const char* flags)
{
   	Packet* p = 0;
    int n = 0;

	assert (size_ > 0);

    n = 1 + (( nbytes - 1 ) / size_);
    int ntot = n ;

	if (nbytes == -1) {
		printf("Error:  sendmsg() for UDP should not be -1\n");
		return;
	}

	// If they are sending data, then it must fit within a single packet.
	if (data && nbytes > size_) {
		printf("Error: data greater than maximum UDP packet size\n");
		return;
	}

    // double local_time = Scheduler::instance().clock();
    while ( n > 0) {
		p = allocpkt();
		hdr_rtp* rh = hdr_rtp::access(p);
		// add "beginning of talkspurt" labels (tcl/ex/test-rcvr.tcl)
        if (flags && (0 ==strcmp(flags, "NEW_BURST"))) {
			rh->flags() |= RTP_M;
		}

        if ( n > 1 ) {
        	// non-last packet
            rh->flags() &= ~RTP_M;
            hdr_cmn::access(p)->size() = size_;
        } else {
        	// last packet
			rh->flags() |= RTP_M;
            hdr_cmn::access(p)->size() = nbytes - ( ntot - 1 ) * size_;
        }

        n--;
        rh->seqno() = ++seqno_;
        hdr_cmn::access(p)->timestamp() = NOW;
		p->setdata(data);

		target_->recv(p);
	}
	idle();
}

void UdpAgent::recv(Packet* pkt, Handler*)
{
	if (app_ ) {
		// If an application is attached, pass the data to the app
		hdr_cmn* h = hdr_cmn::access(pkt);
		app_->process_data(h->size(), pkt->userdata());
	} else if (pkt->userdata() && pkt->userdata()->type() == PACKET_DATA) {
		// otherwise if it's just PacketData, pass it to Tcl
		//
		// Note that a Tcl procedure Agent/Udp recv {from data}
		// needs to be defined.  For example,
		//
		// Agent/Udp instproc recv {from data} {puts data}

		PacketData* data = (PacketData*)pkt->userdata();

		hdr_ip* iph = hdr_ip::access(pkt);
                Tcl& tcl = Tcl::instance();
		tcl.evalf("%s process_data %d {%s}", name(),
		          iph->src_.addr_ >> Address::instance().NodeShift_[1],
			  data->data());
	}
        // Metric for session delay
        hdr_rtp* rh = hdr_rtp::access(pkt);
        // hdr_cmn* cm = hdr_cmn::access(pkt);

        /*fprintf (stderr, "now %f last %f %s %f\n",
                        NOW, cm->timestamp(), ( rh->flags() & RTP_M ) ? "* " : "  ",
                        NOW - cm->timestamp()); */

        if ( rh->flags() & RTP_M ) {
                hdr_cmn* cm = hdr_cmn::access(pkt);
                Stat::put("e2e_session_delay", fid_, NOW - (cm->timestamp()) );
        }

	Packet::free(pkt);
}


int UdpAgent::command(int argc, const char*const* argv)
{
	if (argc == 4) {
		if (strcmp(argv[1], "send") == 0) {
			PacketData* data = new PacketData(1 + strlen(argv[3]));
			strcpy((char*)data->data(), argv[3]);
			sendmsg(atoi(argv[2]), data);
			return (TCL_OK);
		}
	} else if (argc == 5) {
		if (strcmp(argv[1], "sendmsg") == 0) {
			PacketData* data = new PacketData(1 + strlen(argv[3]));
			strcpy((char*)data->data(), argv[3]);
			sendmsg(atoi(argv[2]), data, argv[4]);
			return (TCL_OK);
		}
	}
	return (Agent::command(argc, argv));
}
